[llvm] [GlobalIsel] combine insert vector element (PR #89363)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

```
def freeze_of_not_undef_and_poisen : GICombineRule<
   (defs root:$root),
   (match (G_FREEZE $root, $src),
          [{ return isGuaranteedNotToBeUndefOrPoison(${src}.getReg(), MRI); }]),
   (apply (GIReplaceReg $root, $src))>;
```


https://github.com/llvm/llvm-project/pull/89363